碾压混凝土坝长期服役性能劣化的多因素协同驱动与干预研究

Roller Compacted Concrete has aroused a revolution in dam construction technology in recent years. More and more RCC dams have been built over the past 40 years, especially in China. The security performance, durability and environmental performance of RCC are related to dam safe operation behavior. And the bond quality among RCC layers is closely linked with dam seepage and stability against sliding. With the construction of 200m high RCC dams, it is urgent to be carried out that multi factor synergy drive and intervention on RCC dam long-term service performance degradation targeted RCC dam structural and environmental characteristics, which can provide technical support for engineering design, construction, management and disease control, etc. This project is proposed to take monitoring data and detection information, theoretical analysis, numerical simulation and model test in systematic studies on the interactive evolution mechanism of RCC material and structure under the combination of mechanical elements with multiple environment elements, multi-factor synergy drive mechanism of RCC dam service performance degradation, the disease process identification, early warning model and degradation intervention techniques. The project will reveal the multi-factor synergy drive law of RCC dam long-term service performance degradation and establish degradation early warning and intervention models. The popularization and application of these methods and models in practical engineering will provide scientific and technical support for long-term health service of RCC dam in China finally.

作为近40年来发展起来的新兴坝型，采用碾压混凝土筑坝技术的国家日益剧增，碾压混凝土的安全性、耐久性和与环境的适应性等关系到大坝安全运行，特别是层间结合质量直接关系到大坝的防渗性和层间抗滑稳定性。随着200m级高碾压混凝土坝的建设，亟待针对碾压混凝土坝工程和服役环境特征，开展碾压混凝土坝长期服役性能劣化的多因素协同驱动与干预方面的基础理论和方法攻关，为工程设计、建设、管理和病害防治等提供科技支撑。本项目拟利用监测资料和检测信息、理论分析、数值模拟、模型试验等，重点开展力学要素与多重环境要素联合作用下碾压混凝土材料与结构交互演化机理、碾压混凝土坝长期服役性能劣化的多因素协同驱动机制、劣化过程辨识与预警模型和劣化干预技术等的系统研究，旨在揭示碾压混凝土坝长期服役性能劣化的多因素协同驱动规律，提出劣化预警和干预的方法，并将研究成果推广应用于实际工程，以期为我国碾压混凝土坝长效健康服役提供科技支持。

碾压混凝土坝结合了常态混凝土坝结构强度高与碾压土坝施工简单的优点，具有水泥用量少、施工速度快及工程造价低等优势，但筑坝技术应用历程较短，迫切需要研究综合反映层面影响的安全保障理论和方法，突破有关技术瓶颈。为此，聚焦碾压混凝土坝长期服役性能劣化特性，首先，研究了典型环境因素和力学因素协同作用下碾压混凝土力学特性演化和破坏机理，剖析了碾压混凝土坝材料特性演化规律及其微结构的损伤劣化过程，揭示了结构性能劣化累积的力学规律与转异效应。其次，探究了碾压混凝土坝层面渗透和裂缝等局部损伤扩展演变规律，挖掘了局部损伤主要影响因素驱动规律，建立了局部损伤诊断的熵变模型，从而揭示了碾压层面局部损伤转异对大坝整体稳定性的影响机制。再次，通过剖析碾压混凝土坝病变和失事的主要劣化模式及典型特征，建立了碾压混凝土坝病变过程和服役性态劣化监控模型，构建了碾压混凝土坝长期服役性能预警指标体系和多指标时空联合预警模型。在此基础上，拟定了碾压混凝土坝结构性态灾变的控制荷载组合模式和控制准则，建立了局部病险隐患修复措施最优化决策模型，提出了干预效果的定性评价和云模型量化方法。依托本项目，出版著作2部，发表论文43篇，培养了3名博士研究生和9名硕士研究生，研究成果应用于KLSK水利枢纽、周宁抽蓄电站等多座碾压混凝土坝工程，获2020年水力发电科技进步一等奖1项。本成果为工程安全提供了源头的理论依据和技术支撑，有力地推动了水利行业科技进步和水利工程学科发展。